BOSTON For the first time since he was fired as CEO in June, Arthur T. Demoulas parked at Market Basket’s headquarters in Tewksbury Thursday morning and began his workday.

Hundreds of workers greeted him, back on the job too just hours after the deal was signed for Demoulas to buy out his rival cousin in the family-owned business.

Demoulas climbed onto the back of pickup truck and told workers he loved them. “You, you and only you, have taught the professors and the CEOs that the workplace here at Market Basket is so much more than just a job,” he said to cheers.

Many of the company’s 25,000 employees can hardly believe it. They brought the $4 billion chain to a standstill — and made history — by winning back their CEO.

“There’s no words for it,” said Bill Nascimento, laughing. He’s a bakery manager at the Fitchburg store. “I’m just happy. This is what we were dreaming every single day.”

At a Market Basket warehouse, the forklifts were rolling again.

“These guys are loading the trucks going to the stores. These are all loaded up, full trailers. Gonna get this work out of here,” said warehouse manager Brian Kelleher, who knows that the sooner stores have food on their shelves, the sooner Market Basket can make money again.

“You got dog food, you got tuna fish, you got pickles. I mean, you’ve got everything that these people need right now to get their groceries in their cupboards,” Kelleher said. “Try to get those customers back on board with us, which I’m sure they will be.”

But that’s an open question. The walkout forced customers to do their grocery shopping elsewhere, and they may not all come back. It could also take weeks to restore relationships with food suppliers.

Frank Hoy, who researches family businesses at Worcester Polytechnic Institute, says after losing millions of dollars, Market Basket is now in a very different financial position.

“Whatever happens, you know, there’s gonna be debt to be serviced that this company hasn’t dealt with before,” Hoy said. “And that almost certainly means belt-tightening.”

That’s because as part of the deal, returning CEO Arthur T. Demoulas is replacing his rival family members with new investors. He’s reportedly getting money from a private equity firm and a commercial bank. The company culture may be stronger than ever in this astounding victory, but the worker walkout has resulted in new test for Market Basket.